The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the inventors hereof, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted to be prior art against the present disclosure.
Wireless local area networks (WLANs) operate under WLAN standards such as the Institute for Electrical and Electronics Engineers (IEEE) 802.11a, 802.11b, 802.11g, and 802.11n Standards. The 802.11 standards may specify transmission protocols and data frame formats for data packets. For example, the 802.11 standards may adopt a physical layer convergence procedure (PLCP), under which the PLCP protocol data unit (PPDU) format is used for preamble. The existing 802.11 PPDU in 2.4/5 GHz has a mixed format structure, which includes legacy 802.11a/g portion of preambles and other format portions of preambles suitable for more recently developed 802.11 standards. Such a mixed format preamble is effective in backward compatibility and performance. Thus, because of the mixed structure, a transmission mechanism for the preamble is needed to adapt to both the legacy portion and the non-legacy portion, which can be compatible with the more recently developed 802.11 standards.